Environmental effects on flavour development in Australian - grown strawberry varieties

The volatile compositions of two popular strawberry varieties, Albion (US-bred) and Juliette (Australian-bred), grown in Australia were analysed with comprehensive two-dimensional gas chromatography (GC×GC) combined with time-of-flight mass spectrometry (ToFMS). The data processing method created was deemed to be sufficiently robust, allowing the comparison of sample chromatograms within a harvest season as well as between seasons with relative ease. Ninety four compounds were tentatively or positively identified between the two varieties of which 20 have apparently not been previously reported to be components of strawberry volatiles. It was determined that Albion and Juliette have comparable total soluble solids contents close to 11 °Brix. However, since Juliette exhibited a lower titratable acidity content than Albion, it consequently has a slightly larger sugar:acid ratio. The presence of 2,5-dimethyl-4-hydroxy-(2H)-furan-3-one (furaneol) was detected only in the extracts of Juliette and this variety also had a higher area percentage of 2,5-dimethyl-4-methoxy-(2H)-furan-3-one (mesifuran), according to the sampling protocol. These experimental results offer possible explanations as to why Juliette is perceived to have a sweeter flavour than Albion. The major aim of this research was to study the effect of Australian climate on flavour development in strawberries of these two varieties, which were cultivated in the field for three seasons (2008/09; 2009/10; 2010/11). Rigorous statistical analyses were performed to identify the effects of genotype, the environment, and G×E interaction on fruit quality parameters and flavour-associated volatile compounds. For fruit quality, the genotypic effect was most important for pH, titratable acidity and sugar:acid ratio while the environmental effect was most important for total soluble solids, which is assumed to be indicative of sugar content. Genotypic variation was found to be predominant for majority of the volatile compounds identified between Albion and Juliette, and mostly overshadowed the environmental effect and G×E. The genotypic effect on flavour development justifies the need for breeding programs for production of varieties with good flavour under local environment. The presence of G×E reminds that overseas varieties may not necessarily perform well under local climatic conditions

Chemical characterisation of two Australian-grown strawberry varieties by using comprehensive two-dimensional gas chromatography-mass spectrometry

The volatile compositions of two strawberry varieties ('Albion' and 'Juliette') grown in Australia were analysed with comprehensive two-dimensional gas chromatography (GC × GC) combined with time-of-flight mass spectrometry (ToFMS). A suitable data processing method was created that should be sufficiently robust to compare sample chromatograms within a harvest season as well as between seasons with relative ease. Ninety-four compounds were tentatively or positively identified between the two varieties of which 20 have apparently not been previously reported to be components of strawberry volatiles. It was determined that Albion and Juliette have comparable total soluble solids content close to 11 °Brix. However, since Juliette exhibited a lower titratable acidity content than Albion, it consequently has a slightly larger sugar/acid ratio. The presence of 2,5-dimethyl-4-hydroxy-(2. H)-furan-3-one (furaneol) was detected only in Juliette and this variety also had a higher area percentage of 2,5-dimethyl-4-methoxy-(2 H)-furan-3-one (mesifuran), according to the sampling protocol. These experimental results offer possible explanations as to why Juliette is perceived to have a sweeter flavour than Albion

Genotypic and environmental effects on flavor attributes of 'Albion' and 'Juliette' strawberry fruits

This work is aimed at investigating the genotypic and environmental effects on flavor attributes of two strawberry varieties, in particular, the Australian variety Juliette and the Californian variety Albion, when cultivated in the open field. Flavor quality parameters (i.e. pH, titratable acidity, total soluble solids content and sugar/acid ratio) and volatile compositions of these two genotypes were evaluated over ten harvest dates in one growing season. Correlations have been established between these flavor attributes with variations in air and soil temperatures, photosynthetically active radiation, relative humidity, soil moisture, and rainfall, during the growing season. While genotype was the major source of phenotypic variation for pH, titratable acidity and sugar/acid ratio, the total soluble solids content was more dependent on environmental conditions during production than on genotype. Fluctuations in soil and air temperatures, in particular, were found to significantly influence the total soluble solids content of strawberries. Furthermore, the effect of genotype was, for many volatile compounds, stronger than that of the environment. The genotype-by-environment interactions were highly significant for the four quality parameters, as well as for a majority of the volatile compounds. A set of environmental conditions have also been identified, which may be conducive for the production of highly flavorsome strawberries

Development of molecular markers associated with strawberry quality traits using a subtracted diversity array

The improvement of strawberry (Fragaria × ananassa Duch.) quality such as flavour, day-neutrality, disease resistance, fruit firmness and colour through Australian Strawberry Breeding Program are the main concerns of local strawberry industries in recent years. This study aims to develop molecular markers closely linked to genes controlling flavour and day-neutrality traits by using a Subtracted Diversity Array for the initial marker discovery. In the present study, phenotypic characterization of two commercial strawberry cultivars ('Albion' and 'Juliette'), and three promising breeding lines with intense flavour (07-102-41, 07-095-35 and 04-069-91) were evaluated using solid phase microextraction (SPME) coupled with two-dimensional gas chromatography (GC × GC) and time-of-flight mass spectrometry (TOF-MS). Fisher's ratio was employed to select the key flavour compounds which could discriminate the breeding lines from the commercial cultivars. To determine whether flavour intensity is controlled by copy number of a particular gene, a "copy number" microarray was constructed by printing the genomic DNA of strawberry cultivars with different ploidy levels, ranging from haploid (from isolated microspores) to octoploid, and were hybridised with the respective genes as targets. The relationships among the five strawberry genotypes were determined by Principal Component Analysis and Hierarchical Cluster Analysis. 'Albion' was classified as the out group of the cluster whereas the two breeding lines, 07-102-41 and 07-095-35, were grouped together, followed by 04-069-91 and 'Juliette'. All these data will provide useful information for DNA pooling in the subsequent Subtracted Diversity Array construction. Correlation studies will be performed between the subtractive clones and the aroma profiles to deduce the most promising DNA sequences corresponding to key flavour compounds

Instrumental Food Analysis

The instrumental analysis of foods is an important step in food processing and manufacturing companies because of the presence and interactions of various compounds in foods during storage and processing. While traditional methods are still used, most analysis involves the use of different instruments. This chapter is structured to provide a description of the information each technique can provide, a simple explanation of how it works and examples of its application, and facilitates comparison of techniques. The focus of this chapter is on spectroscopic, chromatographic and electrophoretic methods, including specific examples of instruments such as capillary electrophoresis, high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), atomic absorption, emission and inductively coupled plasma, fluorescence spectroscopies, gel electrophoresis, etc., among many others. © Springer-Verlag Berlin Heidelberg 2015